The flower petals of the calendula plant (Calendula officinalis), or pot marigold, have been used for medicinal purposes since at least the 12th century. Calendula is native to Mediterranean countries but is now grown as an ornamental plant throughout the world. It is not the same as the annual marigold plant that’s often grown in gardens, however.

Calendula has high amounts of flavonoids, plant-based antioxidants that protect cells from being damaged by unstable molecules called free radicals. Calendula appears to fight inflammation, viruses, and bacteria.

Traditionally, calendula has been used to treat stomach upset and ulcers, as well relieve menstrual cramps, but there is no scientific evidence that calendula works for these problems. Today, calendula is often used topically, meaning it’s applied to the skin.

Calendula has been shown to help wounds heal faster, possibly by increasing blood flow and oxygen to the affected area, which helps the body grow new tissue. The dried petals of the calendula plant are used in tinctures, ointments, and washes to treat burns, bruises, and cuts, as well as the minor infections they cause. Calendula also has been shown to help prevent dermatitis or skin inflammation in breast cancer patients during radiation therapy.

Calendula seed: Calendula seed is an after-ripener. That is, the seed germinates better after 6 months of storage than if planted immediately after maturity. This is an adaptation that allows the calendula seed to lie dormant and unsprouted in the soil all winter long, germinating only in the spring.

The calendula seed itself comes in various shapes. The black ones that look like coiled alligators make nice plants, but the big beige calendula seeds that may easily be mistaken for pieces of chaff actually make stronger seedlings.

Cultivation: Calendula is easily grown from seed and may be sown directly in the garden from early spring on into summer, with plenty of time left to get a good harvest of flowers. Tolerant of poor soils, calendula will grow in partial shade or full sun. The plant requires regular watering. Sometimes known as “pot marigold,” calendula is easily grown in pots on the doorstep or in window boxes. Ideal for children, the seeds are large and easily handled, and germination is almost assured even if planted by the inexperienced gardener. Sow about ¼ inch deep and pat down the row. Keep weeded and thin to 6 inches to 1 foot apart. The first flowers are produced only 40 to 50 days after seed germination.

Harvesting and processing the flowers: Harvest is best done in the late morning, after the dew dries. As soon as the flowers come into their prime, pick them off. After the first harvest, pick again in a few days, when the newly developing flowers reach maturity. Spread the calendula flowers on screens to dry, in the shade, and turn and stir them several times daily. As soon as the calendula flowers are dry, store them in plastic bags or glass jars. A forced-air dehydrator is preferred for large-scale production of calendula flowers.

Practical uses: Calendula is usually used externally for its antiseptic and healing properties in treating skin infections, cuts, punctures, scrapes, burns and chapped or chafed skin or lips. The tea or the tincture in water can be swished and swallowed in order to help heal oral lesions, sore throat, or gastric ulcer. Calendula has a good history of external use in the treatment of varicose veins. The fresh flowers are masticated, reduced to a paste with water in a blender, or rubbed directly onto affected areas. The dried flowers are best made into an aromatic infused oil, tea, or tincture. To test the tincture for quality, apply one drop to the surface of a hand-held mirror and wait until the alcohol dries off. Once dry, there should remain a raised droplet of sticky, golden resin.